Early diagnosis of invasive pneumococcal disease by Gram staining of blood culture during incubation

Abstract

We report a case of invasive pneumococcal disease (IPD) that was presumably diagnosed by Gram staining of blood in culture bottles still under incubation. A man in his sixties with chief complains of generalized fatigue and chill was brought to our Emergency Department. On arrival at the hospital, spreading purpura was observed in his whole body, and his general condition deteriorated rapidly after admission. To identify the causal pathogens as soon as possible, we performed Gram staining of a blood culture before an automated system showed positive results. The Gram staining showed Gram-positive diplococci, and the rapid urinary antigen test was positive for Streptococcus pneumoniae. We finally diagnosed him as having IPD earlier than the usual process but he died without any improvement of his clinical condition. This case indicates that Gram staining of cultured blood can be used to detect pathogenic bacteria earlier than the usual blood culture system. Although there are some issues that need to be resolved before implementing this method, it is clearly worth considering for further investigation.